Vocabulary Vocabulary ReviewReview
Ch 33 – Sponges, Ch 33 – Sponges, Cnidarians, and Cnidarians, and
CtenophoresCtenophores
An aquatic invertebrate of the
phylum Porifera that attaches to stones or plants and that has a
porous structure and a tough, elastic skeleton
Sponge
Describes an organism that
remains attached to a surface for its
entire life and does not move
Sessile
Any of the flagellate cells that line the cavities of a
sponge
Choanocyte
One of the small openings in a sponge’s body through which water enters
Ostium
An opening in a sponge’s body through which
water exits
Osculum
A fibrous protein that contains
sulfur and composes the fibers of the
skeleton of some spongesSpongin
A needle of silica or calcium
carbonate in the skeleton of some
sponges
Spicule
In an aquatic animal, a method
of feeding in which the animal traps organic material that is floating in the surrounding
waterFilter feeding
Within the body wall of a sponge, a specialized cell that crawls about and delivers nutrients from the choanocytes to the rest of the body
cells
Amoebocyte
An asexual reproductive
structure produced by some
freshwater sponges
Gemmule
The regrowth of missing tissues or
organs
Regeneration
An organism that has both male and
female reproductive
organs
Hermaphrodite
A free-swimming, jellyfish-like and often
umbrella-shaped sexual stage in the life
cycle of a cnidarian; also a jellyfish or a
hydra
Medusa
A form of a cnidarian that has
a cylindrical, hollow body and that is usually
attached to a rock or to another
objectPolyp
The outer surface layer of cells of a plant or animal
Epidermis
In cnidarians, the layer of cells
surrounding the digestive tract
Gastrodermis
In cnidarians, the jellylike material located between the ectoderm and
the endoderm
Mesoglea
A cavity that serves both
digestive and circulatory
purposes in some cnidarians
Gastrovascular cavity
A flexible appendage with which an animal
feeds itself, grasps objects, or feels its
environmentTentacle
A stinging cell of a cnidarian
Cnidocyte
In cnidarians, a stinging cell that is used to inject a
toxin into prey
Nematocyst
In cnidarians, a network of nerve cells
that lacks a central control; impulses pass in any or all directions
to produce a generalized response
Nerve net
The free-swimming, ciliated larva of a
cnidarian
Planula
A limestone ridge found in tropical
climates and composed of coral fragments that are deposited around
organic remains
Coral reef
A cell that is found on the tentacles of a ctenophore and
that secretes a sticky substance
Colloblast
In ctenophores, a sensory structure that enables the
animal to sense its orientation in water;
in annelids, a ciliated plate located
at the back of the larvaApical organ
The production of light by means of
a chemical reaction in an
organism
Bioluminescence